This invention relates to oxide refractory material having a fine crystal structure; and a process and apparatus for making the same. Oxide refractory materials having a fine crystal structure are useful as refractory grain, or more particularly, as abrasive grain for inclusion in bonded abrasives such as grinding wheels and the like. For such grinding purposes, it is highly desirable for the abrasive grain to have as fine a crystal structure as possible, since this gives toughness to the abrasive grain. Previous methods of making abrasive grain having a fine crystal structure from oxide refractory materials have been successful in producing crystal sizes on the order of 100 to 300 microns. Finer crystal size and greater toughness are still desired, however. It is, therefore, an object of this invention to produce a new and improved oxide refractory material, useful as an abrasive grain, having a crystal structure finer than that heretofore available. Another object of this invention is to provide a novel process for producing such abrasive grain. Still another object is to provide novel apparatus for producing such grain. Other objects will be apparent from the specification.